The caponad spider genus Nopsides Chamberlin was established on the basis of juvenile specimens from Isla Cerralvo in the Gulf of California. Adult males and females of the type (and only known) species, N. ceralbonus Chamberlin, are described for the first time, and the species is newly recorded from the Mexican mainland as well as the Baja peninsula. These animals are nopines (i.e., have subsegmented tarsi), can easily be recognized by their unique eye pattern (with four eyes in two widely separated rows), and are notable for the modifications of the inferior claws. In both sexes, the inferior claw is greatly elongated on legs I and II, but is missing entirely on legs III and IV. A single juvenile specimen, reportedly taken in Peru, shares these somatic characters and suggests that the genus might be more widespread. In a supplement, the genus Amrishoonops Makhan and Ezzatpanah is placed as a junior synonym of the anapid genus Pseudanapis Simon.